Process for the production of artificial teeth



March 18, 1930. K, TAEscHNER 1,751,178

PROCESS FOR THE PRODUCTION OF ARTIFICIAL TEETH Filed June 14, 1927 ZZZZW Patented Mar. 18, 1930 PATENT OFFICE KURT TAESGENER, OF DUBEN, GERMANY PROCESS FOR THE PRODUCTION OF ABTIFIGLALTIETE Application filed June '14, 1927, Serial No.

Artificial anatomic aaa (so-called false teeth) have already been produced, which were provided with protuberances and hollows upon their opposite grinding surfaces, these protuberances and hollows registering in the central bite, that is to say, fitting upon one another and passing h each other in the other biting and grin ingmotions of the teeth, the said hollows and protuberances together forming the grinding surfaces. Moreover, attention has already been given to making the hollows and protuberances of the grmding surfaces so that they are adapted as much as possible to the natural teeth in age of cutting, so that they do not hinder the natural grinding motions, which can be principally difierentiated as back bite, side bite, (either left or right) and forward bite. For this purpose an original form of the teeth has been geometrically constructed, out of which the artificial tooth is produced by additional working by hand. With all known artificial teeth, however, even when followin the natural teeth in age of cutting, the grin' ing surfaces have been more or less arbitrarily shaped, and little attention has been paid to the natural wearing away of the natural teeth in'advanced age and to other abnormal alterations in shape arising from particular circumstances. Therefore all hitherto known artificial teeth have the common draw-b ack, that the projecting or sunken ortions provided upon the grinding suraces engage in one another and have the correct contact in the central bite, but largely or entirely lose the latter on executing the natural grinding motions, so that they are not capable of their function of brealn'ng the food up finely.

On executing the grinding motions the I artificial teeth are caused to tip on account of the arbitrary arrangement of the grinding surfaces, which when the teeth pass over one another becomes disturbing so that the.

artificial teeth become loosened in their settings and if they are working together with natural teeth, the latter become loosened in the jaw by reason of improper pressure. This faulty action of the artificial teeth can 0 only be attributed to the fact that their pro- 198,799, and in Germany January 22, 1927.

duction is effected from the point of view of making whole blocks of teeth by means of complicate'ddevices in a purely mechanical manner out of a block of plaster of Paris, the original form consisting of plane surfaces meeting one another angularly which after having been worked with a knife by hand, form blunt angles upon the grinding surface, each of which is limited by three surfaces forming a pyramid, and which thus only take 00 into consideration the three grinding motions, namely forward bite, side bite and back bite. In order to 've the so formed pyramid shapes, which fit into one another exactly or wit out any gap worth mentioning when the jaws are closed, a soiilewhat enlarged possibility of motion, an endeavour is made to 've the grinding surfaces a better shape, y arbitrarily rounding off the sharp points and corners with a knife by hand, but the shape so obtained does not correspond to the naturally worn'away grinding surfaces of the natural teeth. When grinding the food the under jaw does not make angular motions but rather motions in th form of an are, which are composed of umerable separate motions. It is therefore impossible with the geometrically constructed grinding surfaces of the known artificial teeth to carry out the grindin motions so completely that a perfect grindlng of the food results. The object of the present invention is to produce artificial teeth, which have on their opposite grinding surfaces protuberances and hollows consisting of plane or curved surfaces, registering with one another, in a known manner in the central bite, that is fitting upon one another and passing by one another in the other grinding motions of the teeth, and together forming the grinding surfaces, wherein, however, the disadvantages of the known artificial teeth of similar type are obviated, in that the grinding and mastication paths of the natural teeth are exactly given to the artificial teeth, having regard to the alterations in shape arising from the natural wearing away in advanced age or such circumstances, so that the artificial teeth without disturbing the natural movements of the jaws or the contact and the acv .of the natural teeth or take over this work.

The production of the artificial teeth is effected according to the invention by employing a model of the upper and lower'jaw formed in adesired or known'manner. from a material which will not wear away, and

made according to a complete natural set, with the alterations in shape arising from the natural wearing away of the grinding surfaces in advancedage and from other circum-' stances, from which model theteeth to be produced are taken either singly or in pairs and replaced by other model teeth formed out of a material which is easily ground away and having anatomic unworn grinding surfaces,

and by imitating the natural biting, chew-' ing and grinding motions by means of reciprocatory motions of the two models of the jaws carried out either by hand or by means of a mechanical device, the grinding and mastication paths of the natural teeth being given to the model teeth set in the model of the jaw, that is the grinding surfaces which are not worn away are"'ground down on the opposite grinding surfaces of the model of the jaw. The ground away mode] teeth so produced then serve as a model for the production of the false teeth ready for use which do not need any further working and which fit with their oblique or flat grinding or mastication paths exactly into the grind- I ing surfaces of the patients own teeth which, may be more or less worn away or abnormal.

The drawings show the model of the upper and lower jaw, made according to a full and well worn natural set of teeth, employed for the production of artificial teeth, and seen in side elevation.

Figs. 1 and 2 show side elevations of two jaw models in which teeth are to be replaced.

In Fig. 1, the first lower bicuspid. c and simultaneously With it the upper eye-tooth d and the first upper bicuspid f are to be ground in, that is their original model isto be produced, by means of the two jaw models a and b, which are formed froma material which will not wear away. For this purpose'the teeth concerned are taken out of the jaw models and after shortening of the left angle of the second lower bicuspid 9, replaced by model teeth formed out of plaster or other material which is easily worn away and having anatomic unworn grinding surfaces, which teeth are secured in the jaw models a and b by means of a suitable grinding material, such as wax, plaster, and so forth. By the insertion of layers hthe model teeth can be adjusted in height. The grinding-in of the model teeth is effected if the natural grinding motions are imitated b reciprocatory motions of the two jaw mo els a and b either by hand or by means of any suitable mechanical device, when the remaining teeth of the two jaw models act as guides and grinding surfaces. a

When these model teeth are completely ground in, then the remaining teeth are treated in the above-described manner. As shown in Fig. 2 the second lower bicuspid g and the second upper bicuspid i are taken out of the jaw models a and b, the left angle of the first lower molar shortened and the for- The plaster models-of the teeth ground in i in this manner now show the actual shapes of the grinding surfaces of the natural teeth and can serve as models for the production of the necessary fired porcelain teeth for the false set.

In particular cases when for example the bicuspid g is missing in the lower jaw and the two opposite natural upper bicuspids' fand i have an abnormal shape, for which reason the usual commercial false tooth cannot be employed, the dentist will be able to remedythis in this manner, that a model of both 7 upper and lower jaws is produced in the manngr described above out of a hard mass which Wlll not wear away and the plaster model of the missing bicuspid 9 ground in, so that the actual artificial tooth of porcelain can be made accordingly.

'Moreover complete sets of false teeth'can be made in the same manner for patients with abnormal bites, for example, cross bite sets. When grinding in these sets, two-natural sets of teeth, the teeth of which stand in cross bite, are taken as foundation and the unworn model teeth made of plaster are ground as described above by means of jaw models made accordingly.

I claim 1. A method of producing artificial teeth and lower jaws of naturally worn teeth in a hard material, removing pairs of teeth to be replaced from said models, replacing said teeth by unworn anatomical teeth made of.

easily grindable material, grinding said anatomical teeth by imitating the natural biting, chewing and grinding movements of the jaws by means of said models and formin artificial teeth of ahard material from said ground anatomical teeth.

3. A method of producing artificial teeth consisting in forming in hard material models of the upper and lower jaws as affected by wear and alterations in shape, removing a plurality of the teeth from said jaws, removing the corners of teeth in the jaw models adjacent the removed teeth, replacing the removed teeth by anatomical unworn teeth of an easily grindable material, adjusting said anatomical teeth in the upper and lower jaws, grinding said anatomical teeth by imitating the biting, chewing and grinding movements of the jaws by meansof said jaw models, and forming artificial teeth of hard material from said ground anatomical teeth.

4. A method of producing artificial teeth consisting in forming models of the upper and lower jaws of naturally worn teeth in a hard material, removing pairs ofteeth from said models, replacing said removed teeth by anatomical unworn teeth of an easily grindable'material, grinding said anatomical teeth by imitating the natural biting, chew ing and grinding motions by means of said aws, rendering said ground teeth hard, re-

- movmg further teeth from said models, re

placing said further removed teeth by anatomical unworn teeth of an easily grindable material, grinding said further anatomical teeth by imitating the natural biting, chewing and grinding motions by said jaw models, and forming artificial teeth of hard material from the anatomical teeth obtained by the grinding operations.

5. The method of forming an artificial tooth which comprises arranging a model tooth, having at least a soft occlusal surface, in a position similar to that to be occupied by the finished tooth, then moving a cooperating tooth over the model tooth in a manner imitating the natural jaw movements, whereby saidcooperating tooth will cut the proper form in the soft material, then forming a mold embodying the form cut in said soft material, and then forming an artificial tooth from the mold.

KURT TAESCHNER. 

